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Robinson KM. Unsolicited narratives from the Internet: a rich source of qualitative data. QUALITATIVE HEALTH RESEARCH 2001; 11:706-714. [PMID: 11554197 DOI: 10.1177/104973201129119398] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recently, the Internet has become a forum for informal communication. Many--whose voices may have been unheard--can now express themselves through this medium. Rich narratives are available to the qualitative researcher from bulletin boards, guestbooks, Web pages, and listservs on the Internet. In this article, these data sources are defined and described. Strategies for using these data are discussed. One concern with using unsolicited data from the Internet is the protection of human subjects and the requirement for consent. A proposed model describing the process for deciding when such data are publicly available, as defined by the Office for the Protection of Rights of Research Subjects, and when the use of the data requires consent is presented.
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Robinson KM. Rehabilitation applications in caring for patients with Pick's disease and frontotemporal dementias. Neurology 2001; 56:S56-8. [PMID: 11402153 DOI: 10.1212/wnl.56.suppl_4.s56] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The basic principles of rehabilitation philosophy relevant to the care of patients with neurodegenerative diseases, specifically Pick's disease and frontotemporal dementias, are briefly defined. These principles are illustrated by the case study of a patient with a clinical diagnosis of Pick's disease.
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Robinson KM. Linking nurse clinicians to research committees. KENTUCKY NURSE 1999; 47:21. [PMID: 11998144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Abstract
1. Although many studies examine the impact of respite care on caregivers, few studies have examined the impact of such programs on the volunteer respite provider. Results of such formative evaluation studies must be antecedent to the question of whether respite care "works." 2. Fear of persons with Alzheimer's Disease (AD) was a consistent theme verbalized in this study. Educational programs must therefore include more exposure to actual persons with AD. 3. Caregivers with some past experience composed the majority of volunteers in this group (n = 78%). Recruiting former caregivers of deceased persons with AD may be fruitful future areas of study.
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Näär AM, Beaurang PA, Robinson KM, Oliner JD, Avizonis D, Scheek S, Zwicker J, Kadonaga JT, Tjian R. Chromatin, TAFs, and a novel multiprotein coactivator are required for synergistic activation by Sp1 and SREBP-1a in vitro. Genes Dev 1998; 12:3020-31. [PMID: 9765204 PMCID: PMC317191 DOI: 10.1101/gad.12.19.3020] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/1998] [Accepted: 08/10/1998] [Indexed: 01/09/2023]
Abstract
The promoter selectivity factor Sp1 often cooperates with other enhancer-binding proteins to activate transcription. To study the molecular underpinnings of these regulatory events, we have reconstituted in vitro the synergy observed in vivo between Sp1 and the sterol-regulated factor SREBP-1a at the low density lipoprotein receptor (LDLR) promoter. Using a highly purified human transcription system, we found that chromatin, TAFs, and a novel SREBP-binding coactivator activity, which includes CBP, are all required to mediate full synergistic activation by Sp1 and SREBP-1a. The SREBP-binding domain of CBP inhibits activation by SREBP-1a and Sp1 in a dominant-negative fashion that is both chromatin- and activator-specific. Whereas recombinant CBP alone is not sufficient to mediate activation, a human cellular fraction containing CBP can support high levels of chromatin-dependent synergistic activation. Purification of this activity to near homogeneity resulted in the identification of a multiprotein coactivator, including CBP, that selectively binds to the SREBP-1a activation domain and is capable of mediating high levels of synergistic activation by SREBP/Sp1 on chromatin templates. The development of a reconstituted chromatin transcription system has allowed us to isolate a novel coactivator that is recruited by the SREBP-1a activation domain and that functions in concert with TFIID to coordinate the action of multiple activators at complex promoters in the context of chromatin.
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Robinson KM, Kadonaga JT. The use of chromatin templates to recreate transcriptional regulatory phenomena in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1378:M1-6. [PMID: 9739762 DOI: 10.1016/s0304-419x(98)00008-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Grossman M, Mickanin J, Onishi K, Robinson KM, D'Esposito M. Lexical acquisition in probable Alzheimer's disease. BRAIN AND LANGUAGE 1997; 60:443-463. [PMID: 9398392 DOI: 10.1006/brln.1997.1841] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Patients with probable Alzheimer's disease (pAD) were exposed to a new verb in a naturalistic fashion. We probed their knowledge of the word's semantic and grammatical characteristics for several minutes following this exposure, and compared this with their performance on parallel measures assessing known words. Significant differences were seen between pAD patients and controls in the acquisition of the new verb's semantic meaning and its argument structure, but pAD patients did not differ from controls in the acquisition of the new word's grammatical form class. Individual patient analyses demonstrated parallel deficits restricted to the semantic meaning and argument structure of the new word and known words in several pAD patients, suggesting that a selective language impairment contributed to their word learning deficit. This pattern is consistent with an intimate relationship between semantic meaning and argument structure in semantic memory. Other pAD patients had difficulty learning about all aspects of the new word, despite good performance with known words, suggesting that compromised memory may have limited their lexical acquisition.
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Robinson KM. Family caregiving: who provides the care, and at what cost? NURSING ECONOMIC$ 1997; 15:243-7. [PMID: 9362866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Today, there are an estimated 1.6 million people over 65 years of age who require assistance with two or more daily activities. This number is projected to rise to 2.1 million by 2001, with fewer family caregivers expected to be available to provide this informal care. Seventy-two percent of unpaid family caregivers are women, the majority of whom are mid-life daughters or daughters in law. Uncompensated care to the frail elderly requires an average of 28 to 39.9 hours per week of custodial care. The financial impact on informal caregivers includes: 9% of family caregivers who leave the labor force to provide care, 29.4% who adjust their work schedules, and 18.1% who take time off without pay. The estimated annual value of uncompensated kin care in 1990 was $18 billion. Thirty-two percent of all family caregivers are categorized as poor or near-poor at incomes that are less than 125% of the federal poverty level.
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Abstract
Long-term care provided by family members is the central care of our current health care system. The purpose of this article is to review the family's role in long-term care. Issues such as cost containment and inequities in our current social policy are reviewed. Suggestions for future directions in social policy are presented.
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Dibrov E, Robinson KM, Lemire BD. The COQ5 gene encodes a yeast mitochondrial protein necessary for ubiquinone biosynthesis and the assembly of the respiratory chain. J Biol Chem 1997; 272:9175-81. [PMID: 9083048 DOI: 10.1074/jbc.272.14.9175] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Saccharomyces cerevisiae is a facultative anaerobe capable of meeting its energy requirements by fermentation and is thus an ideal system for studying the biogenesis of respiring mitochondria. We have isolated a respiration-deficient mutant exhibiting a pleiotropic loss of the mitochondrial electron transport chain. The corresponding wild-type gene, COQ5, was cloned, sequenced, and able to restore respiratory growth. Deletion of the chromosomal COQ5 gene results in a respiration deficiency and reduced levels of respiratory protein components. Exogenously added decylubiquinone can partially restore electron transport chain function to mitochondrial membranes from the deletion mutant. The COQ5 nucleotide sequence predicts a polypeptide of 307 amino acids containing a mitochondrial targeting signal. COQ5p is 43% identical to the polypeptide predicted by the Escherichia coli open reading frame, o251 (1). The COQ5 gene, when introduced into E. coli, complements the respiratory deficiency of an ubiE mutant that maps near o251, suggesting that it is the yeast homolog of the ubiE gene product. We conclude that the COQ5 gene encodes the mitochondria-localized 2-hexaprenyl-6-methoxy-1,4-benzoquinone methyltransferase of the yeast ubiquinone biosynthetic pathway.
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Grossman M, Mickanin J, Robinson KM, D'Esposito M. Anomaly judgments of subject-predicate relations in Alzheimer's disease. BRAIN AND LANGUAGE 1996; 54:216-232. [PMID: 8811954 DOI: 10.1006/brln.1996.0072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Claims that patients with probable Alzheimer's disease (AD) have semantic memory difficulty have received equivocal support. A common assumption has been that defining or core information determines the truth value of word meaning on measures requiring semantic memory such as category membership judgments or confrontation naming, but this assumption may not be valid. In the present study, we assessed the comprehension of subject-predicate sentences independent of their truth value by asking AD patients to judge the coherence of statements such as "The tulip is tall" or "*The tulip is jealous." We found that AD patients are significantly more impaired than controls at judging the coherence of these simple subject-predicate sentences. Moreover, AD patients were more successful at judging the coherence of statements that contain attributes with a narrow scope of reference compared to attributes with a broad scope of reference. These findings support the hypothesis that AD patients have a semantic memory impairment and suggest a specific deficit processing the network of semantic relations underlying word meaning in semantic memory.
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Grossman M, D'Esposito M, Hughes E, Onishi K, Biassou N, White-Devine T, Robinson KM. Language comprehension profiles in Alzheimer's disease, multi-infarct dementia, and frontotemporal degeneration. Neurology 1996; 47:183-9. [PMID: 8710075 DOI: 10.1212/wnl.47.1.183] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We assessed language functioning in 116 age-, education-, and severity-matched patients with the clinical diagnosis of Alzheimer's disease (AD), multi-infarct dementia (MID) due to small-vessel ischemic disease, or a frontotemporal form of degeneration (FD). Assessments of comprehension revealed that patients with AD are significantly impaired in their judgments of single word and picture meaning, whereas patients with FD had sentence comprehension difficulty due to impaired processing of grammatical phrase structure. Patients with MID did not differ from control subjects in their comprehension performance. Traditional aphasiologic measures did not distinguish between AD, MID, and FD. Selective patterns of comprehension difficulty in patients with different forms of dementia emphasize that language deficits cannot be explained entirely by the compromised memory associated with a progressive neurodegenerative illness.
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Robinson KM, Grossman M, White-Devine T, D'Esposito M. Category-specific difficulty naming with verbs in Alzheimer's disease. Neurology 1996; 47:178-82. [PMID: 8710073 DOI: 10.1212/wnl.47.1.178] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We studied 20 patients with Alzheimer's disease (AD) on a picture-naming task consisting of frequency-matched pairs of nouns and verbs that were homophonic and homographic (e.g., paint). Intragroup comparisons revealed that verb naming is significantly more difficult for patients with AD than noun naming. An error analysis demonstrated that patients with AD produce significantly more semantic and descriptive errors for verbs than nouns. We correlated verb naming and noun naming with measures of grammatical comprehension, lexical retrieval, and visuoperceptual processing, but there were no selective effects for verbs compared with nouns. Differences in the mental representation of concepts underlying verbs and nouns may account, in part, for the relative difficulty naming with verbs in AD.
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Grossman M, Mickanin J, Onishi K, Robinson KM, D'Esposito M. Freehand drawing impairments in probable Alzheimer's disease. J Int Neuropsychol Soc 1996; 2:226-35. [PMID: 9375188 DOI: 10.1017/s1355617700001168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We evaluated freehand picture production of familiar objects in patients with probable Alzheimer's disease. The overall recognizability of their drawings was significantly compromised. Error analyses revealed the production of category violations and the frequent inclusion of incorrect features in a picture that were borrowed from semantically related objects, suggesting difficulty distinguishing between items with overlapping features sets in semantic memory. Analyses of individual patient drawing profiles also revealed that some patients are disproportionately compromised in expressing a particular perceptual feature, implicating difficulty at the level of perceptual processing. Regression analyses demonstrated the contribution of limited visual attentional resources. We conclude that impaired freehand drawing in probable Alzheimer's disease is multifactorial in nature.
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Robinson KM, Lemire BD. A requirement for matrix processing peptidase but not for mitochondrial chaperonin in the covalent attachment of FAD to the yeast succinate dehydrogenase flavoprotein. J Biol Chem 1996; 271:4061-7. [PMID: 8626740 DOI: 10.1074/jbc.271.8.4061] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Succinate dehydrogenase (EC 1.3.99.1) in the yeast Saccharomyces cerevisiae is a mitochondrial heterotetramer containing a flavoprotein subunit with an 8alpha-N(3)-histidyl-linked FAD cofactor. The covalent linkage of the FAD is necessary for activity. We have developed an in vitro assay that measures the flavinylation of the flavoprotein precursor in mitochondrial matrix fractions. Flavoprotein modification does not depend on translocation across a membrane, but it does require proteolytic processing by the mitochondrial processing peptidase prior to flavin attachment. Since ATP depletion, N-ethylmaleimide, or proteinase treatments of matrix fractions inhibit flavoprotein modification, at least one additional matrix protein component appears to be required. Having previously suggested that the flavoprotein begins folding before FAD attachment occurs, we tested whether the mitochondrial chaperonin, heat shock protein 60, might be necessary. Co-immunoprecipitation of the flavoprotein and the chaperonin demonstrate that the proteins do indeed interact. However, immunodepletion of the chaperonin from matrix fractions does not inhibit FAD attachment. Nonprotein components are also required for flavoprotein modification. In addition to ATP, effector molecules such as succinate, fumarate, or malate also stimulate modification. Together, these results suggest that FAD addition is an early event in succinate dehydrogenase assembly.
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Robinson KM, Lemire BD. Covalent attachment of FAD to the yeast succinate dehydrogenase flavoprotein requires import into mitochondria, presequence removal, and folding. J Biol Chem 1996; 271:4055-60. [PMID: 8626739 DOI: 10.1074/jbc.271.8.4055] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Succinate dehydrogenase (EC 1.3.99.1) in the yeast Saccharomyces cerevisiae is a mitochondrial respiratory chain enzyme that utilizes the cofactor, FAD, to catalyze the oxidation of succinate and the reduction of ubiqinone. The succinate dehydrogenase enzyme is a heterotetramer composed of a flavoprotein, an iron-sulfur protein, and two hydrophobic subunits. The FAD is covalently attached to a histidine residue near the amino terminus of the flavoprotein. In this study, we have investigated the attachment of the FAD cofactor with the use of an antiserum that specifically recognizes FAD and hence, can discriminate between apo- and holoflavoproteins. Cofactor attachment, both in vivo and in vitro, occurs within the mitochondrial matrix once the presequence has been cleaved. FAD attachment is stimulated by, but not dependent upon, the presence of the iron-sulfur subunit and citric acid cycle intermediates such as succinate, malate, or fumarate. Furthermore, this modification does not occur with C-terminally truncated flavoprotein subunits that are fully competent for import. Taken together, these data suggest that cofactor addition occurs to an imported protein that has folded sufficiently to recognize both FAD and its substrate.
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Biassou N, Grossman M, Onishi K, Mickanin J, Hughes E, Robinson KM, D'Esposito M. Phonologic processing deficits in Alzheimer's disease. Neurology 1995; 45:2165-9. [PMID: 8848186 DOI: 10.1212/wnl.45.12.2165] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We investigated phonologic production in patients with mild to moderate Alzheimer's disease (AD) on a repetition task. AD patients produced significantly more speech errors than age-matched controls. AD patients' errors, unlike those of controls, resulted in the transformation of real words into pseudowords, occurred disproportionately in word-initial positions, and were not influenced by the phonologic environment. This pattern of errors suggests a lexical phonologic retrieval deficit in AD.
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Grossman M, Robinson KM, Onishi K, Thompson H, Cohen J, D'Esposito M. Sentence comprehension in multiple sclerosis. Acta Neurol Scand 1995; 92:324-31. [PMID: 8848939 DOI: 10.1111/j.1600-0404.1995.tb00137.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Explanations of sentence processing difficulty in aphasia have implicated slowed information processing speed. We tested this hypothesis by evaluating sentence comprehension in multiple sclerosis (MS), and relating comprehension performance to measures of information processing speed. MATERIAL & METHODS Twenty right-handed, high school-educated, non-demented, native English speakers with clinically definite MS and 16 age- and education-matched control subjects were examined on 3 different sentence comprehension measures that stress grammatical appreciation. Performance was related to quantitative assessments of mental information processing speed. RESULTS Group-wide analyses demonstrated a trend toward sentence comprehension difficulty in MS. Analyses of individual patient profiles identified a subgroup of MS patients who were consistently impaired to a significant extent across all sentence comprehension tasks. Their sentence comprehension difficulty was associated with selectively compromised mental information processing speed. CONCLUSION Sentence comprehension difficulty in MS is associated with slowed information processing speed. This finding supports the claim that information processing speed contributes to sentence processing.
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Robinson KM, Lemire BD. Flavinylation of succinate: ubiquinone oxidoreductase from Saccharomyces cerevisiae. Methods Enzymol 1995; 260:34-51. [PMID: 8592458 DOI: 10.1016/0076-6879(95)60128-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Robinson KM, Steele D. The relationship between health and social support in caregiving wives as perceived by significant others. J Adv Nurs 1995; 21:88-94. [PMID: 7897083 DOI: 10.1046/j.1365-2648.1995.21010088.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This study explored the relationship between health and social support in wives who care for husbands with dementia. In order to understand how significant others begin mobilizing help for caregivers, the significant others' views of the carers' health and social support were analysed. Subjects comprised 75 significant others identified as being familiar with the caregiving situation of a like number of caregiving wives. Hypotheses, which were rejected, predicted that wife caregivers perceived as ill by the significant other would be seen as needing and receiving more social support as reported by the significant other. Findings indicated that healthy caregivers were perceived to have significantly more people in their social network.
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Abstract
The spiritual perspectives of 17 caregiver wives of dementia victims and 23 noncaregiving wives of healthy adults were compared in a pilot study using a convenience sample. Caregiver wives used symbols such as God, and spiritual behaviors such as prayer and forgiveness as coping mechanisms. Caregivers tended to share the problems and joys of living according to their spiritual belief more often than the noncaregiver wives of healthy adults. Caregivers also engaged in private prayer and sought spiritual guidance in making decisions in their everyday life more often. The findings suggest that nursing interventions with churches as a natural network for caregivers may be useful. Prayer, forgiveness, and spiritual reading materials are resources that may be helpful to some caregivers.
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Robinson KM, Rothery RA, Weiner JH, Lemire BD. The covalent attachment of FAD to the flavoprotein of Saccharomyces cerevisiae succinate dehydrogenase is not necessary for import and assembly into mitochondria. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 222:983-90. [PMID: 8026509 DOI: 10.1111/j.1432-1033.1994.tb18949.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Succinate dehydrogenase of the bacterial or inner mitochondrial membrane catalyses the oxidation of succinate to fumarate and directs reducing equivalents into the electron-transport chain. The enzyme is also able to catalyse the reverse reaction, the reduction of fumarate to succinate. The enzyme is composed of four subunits. These subunits include a catalytic dimer composed of a flavoprotein subunit with a covalently bound FAD, and an iron-sulfur protein subunit with three different iron-sulfur centres, which is anchored to the membrane by two smaller integral membrane proteins. The FAD moiety is attached to the flavoprotein subunit by an 8 alpha-[N(3)-histidyl]FAD linkage at a conserved histidine residue, His90 of the Saccharomyces cerevisiae succinate dehydrogenase. By mutating His90 to a serine residue, we have constructed a flavoprotein subunit that is unable to covalently bind FAD. The mutant flavoprotein is targeted to mitochondria, translocated across the mitochondrial membranes, and is assembled with the other subunits where it binds FAD non-covalently. The resulting holoenzyme has no succinate-dehydrogenase activity but retains fumarate reductase activity. The covalent attachment of FAD is therefore necessary for succinate oxidation but is dispensable for both fumarate reduction and for the import and assembly of the flavoprotein subunit.
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Sheetz MJ, Barnhart RL, Jackson RL, Robinson KM. MDL 29311, an analog of probucol, decreases triglycerides in rats by increasing hepatic clearance of very-low-density lipoprotein. Metabolism 1994; 43:233-40. [PMID: 8121308 DOI: 10.1016/0026-0495(94)90251-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
MDL 29311 is an analog of probucol that shares probucol's antioxidant and antiatherogenic properties. When fed to rats as a 1% dietary admixture, MDL 29311 decreased triglyceride levels by 65% without affecting total or high-density lipoprotein (HDL) cholesterol levels. Under the same conditions, probucol decreased triglyceride levels by 23% and total cholesterol levels by 29% (with a corresponding decrease in HDL cholesterol level). MDL 29311 treatment did not affect the rate of triglyceride entry into the plasma. However, MDL 29311-treated rats cleared in vivo-labeled very-low-density lipoprotein (VLDL)-associated [3H]-triglyceride ([3H]-VLDL) over threefold faster than control rats. This increase in clearance led to increased levels of [3H]-lipid in liver and decreased [3H]-lipid in fat, muscle, diaphragm, and kidney of MDL 29311-treated rats 1.5 to 2.0 minutes after injection of [3H]-VLDL. MDL 29311 treatment had no effect on lipoprotein lipase (LPL) or hepatic triglyceride lipase (H-TGL) activities, or on plasma apolipoprotein (apo) C-II-dependent LPL activation. Intravenously injected [3H]-VLDL was allowed to circulate in MDL 29311-treated or control rats for 1 minute, and the undiluted plasma was then perfused through rat livers in a recirculating system. The [3H] in MDL 29311 plasma was cleared threefold faster (t1/2, 1.3 v 3.8 minutes) than the [3H] in control plasma by control livers. Conversely, the [3H] in control plasma was cleared slowly (t1/2 = 3.5 minutes) by the livers of MDL 29311-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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Heineke EW, Johnson MB, Dillberger JE, Robinson KM. Antioxidant MDL 29,311 prevents diabetes in nonobese diabetic and multiple low-dose STZ-injected mice. Diabetes 1993; 42:1721-30. [PMID: 8243818 DOI: 10.2337/diab.42.12.1721] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recent investigations suggest a role for antioxidants in preventing IDDM. MDL 29,311 (4,4'-[methylenebis(thio)]bis](1,1- dimethylethyl)]-phenol) is an analogue of the antioxidant probucol. Administered as a 1% dietary admixture to female nonobese diabetic mice from 4 to 24 wk of age, MDL reduced the prevalence of diabetes from 49 to 4% at 24 wk of age (n = 50-61/group). Discontinuation of treatment at 24 wk of age did not result in a rapid onset of diabetes. Probucol (1%) did not prevent diabetes. Initiating MDL treatment at 4 or 8 wk of age was more effective (19 and 17%, respectively, compared with 60% in control mice) than initiating treatment at 12 wk of age (30% diabetic; n = 28-35/group). A lower dose of MDL (0.1%), started at 4 wk of age, decreased the prevalence of diabetes to 36%. Histopathology indicated that MDL did not prevent insulitis. MDL (0.1%) also was evaluated in combination with immunosuppressants. Compared with control mice (65% diabetic), the combination of MDL and deflazacort was more effective (21% diabetic) than either agent alone (39% diabetic for MDL and 59% diabetic for deflazacort), whereas the effectiveness of MDL, cyclosporin, and MDL plus cyclosporin was similar (39, 38, and 34% diabetic, respectively). In another model of IDDM, the multiple-low-dose streptozocin-injected mouse, MDL (1%) also reduced the prevalence of diabetes when administered beginning 8 wk before streptozocin (55% diabetic vs. 100% of control mice; n = 20-25/group). Probucol (1%) was ineffective. MDL appears effective in preventing the onset of disease in two mouse models of IDDM.
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